Enhanced performance of a silicon microfabricated direct methanol fuel cell with PtRu catalysts supported on few-walled carbon nanotubes

Si-MFCs (Silicon micro fuel cells) are promising power supplies for microelectronic applications, however their development is still at early stages compared to the conventional PEM-FCs (proton exchange membrane fuel cells). There are not many published reports on the durability of Si-MFCs and those available only projected the life-time of standard Vulcan based catalysts. However, the limited durability resulting from carbon corrosion is one of the crucial issues in fuel cells. In this study, Si-MFC with an integrated silicon nanograss diffusion layer is used for the direct methanol fuel cell investigations. The long-term (3-day) performance of PtRu catalysts supported on different carbon supports, namely Vulcan, GNFs (Graphitized carbon nanofibers) and FWCNTs (Few-walled carbon nanotubes), was studied. PtRu-FWCNTs and PtRu-GNFs exhibited respectively 471% (20.0 mW cm−2) and 274% (13.1 mW cm−2) power density enhancements compared to PtRu-Vulcan (3.5 mW cm−2). After 3-day durability measurements, power density stayed at 72%, 68% and 91% of the initial value, respectively for PtRu-FWCNTs, PtRu-GNFs and PtRu-Vulcan. To evaluate the influence of carbon supports as well as the distribution and the size of the nanoparticles on the overall performance of Si-MFCs, further characterizations with Raman, BET (Brunauer-Emmett-Teller), XRD (X-ray diffraction), SEM (Scanning electron microscopy) and TEM (Transmission Electron microscopy) were performed.